1. Field of the Invention
The present invention relates to a gas sampling device and, in particular, to a dual-chamber gas sampling device using thermal convection for accelerating gas diffusion rate, which can be used in all non-dispersive infrared (NDIR) gas concentration analyzer, and for improving the sampling rate and reducing the length of the device.
2. Description of Related Art
A gas sampling device is required for conventional non-dispersive infrared (NDIR) gas concentration analyzer. With prior art gas sampling devices, a gas pump or fan is used such that gas is introduced into a gas chamber by forced convection. By doing so, while reaction time is reduced, a lot of problems, such as noise, vibration, interference due to the noise, excessive power consumption, etc., are caused, thus rendering them unsuitable for use in hand-held or pocket-size battery operated apparatuses. Therefore, there have been gas sampling devices in which chamber of porous materials or chamber having diffusion apertures left all around are utilized. Gas sampling is achieved by using the difference in concentration to generate diffusion. These devices, however, have disadvantages in that the reaction time is relative longer and the chamber has to be longer in length for sufficient sensitivity.
In view of the disadvantages encountered by conventional gas sampling devices described above, the present invention provides a dual-chamber gas sampling device in which, in addition to the diffusion apertures provided on the gas chamber, the temperature difference between the upper and lower chambers is used to increase the gas diffusion rate such that the reaction time is reduced. At the same time, the reflecting surfaces of the reflecting elements which are at right angle with respect to each other are used for transmitting light rays so as to serve the purpose for analyzing gas concentration by non-dispersive infrared, and a single chamber can thus be divided into two chambers for improved arrangement such that the size of the device can be further reduced.